In the manufacture of concrete walls, such as those that make up underground utility vaults, it is useful to have pre-cast apertures available for penetration by pipes, conduits, wires and the like. Such apertures have been provided by positioning core elements between the forms used to cast the wall or vault, so that the cores exclude concrete from the desired locations. To provide circular apertures, cylindrical core elements are employed. The cores may have some compressibility or rim gaskets to accommodate variations in form spacing and remain flush against the form surfaces during casting, to ensure that concrete does not enter the desired voids. The cores normally include a cap, membrane, or other barrier that is readily removed or opened when passage is desired, but which seal out dirt and groundwater from the vault.
One difficulty with casting multiple cores is securing them in a desired position. One past approach is to secure them to one of the form boards. This is time consuming, can lead to irregular positioning, and damages the form boards over time. To avoid these problems, systems exist with solid panels having apertures arranged in a matrix to receive a number of cores. Each such panel has a defined number of apertures in which cores may be installed prior to casting. These are normally fastened to a form board, leading to form damage over time. In addition, a different size and shape of panel must be manufactured and stocked for each possible configuration of holes, leading to increased inventory costs. The inventory concern is only partially addressed by modular panels that employ modular strips that are assembled to form a matrix of apertures. Such existing modules are elongated members with several semicircular cutouts on one or both sides. The length of the module determines the number of apertures in each column, and the number of modules determines the number of rows in the matrix. Again, this system requires inventorying a variety of different lengths. Moreover, it generates only rectangular arrays, when other shapes may be desired (and when a rectangle large enough to encompass the desired shapes would be wasteful of material or conflict with other elements in the intended structure.)
Another problem with existing systems is that there is occasionally a need to accommodate cores, sleeves, or pipes of different diameters in a single assembly. Manufacturing and stocking of a wide variety of part sizes increases costs and inventory burdens.
The embodiment disclosed herein overcomes these disadvantages by providing a support module that interconnects with other support modules to support a number of core elements for encapsulation within a concrete structure. The module has a planar frame defining first and second cutouts. Each cutout has an arc shape so that when modules are assembled, the cutouts of different modules define a circular aperture for closely receiving one of the core elements. Each cutout has a first peripheral arc portion and a concentric second arc portion larger than the first portion. The first portion provides an aperture of a first diameter, and upon removal of the first portion, the second portion provides an aperture of a larger second diameter. The frame having connection elements that to connect with other support modules to securely receive the core elements. The module may include a separately formed arcuate insert fastened to the cutout to provide a smaller aperture